1. Field of the Invention
This invention generally relates to a bicycle internal hub transmission. More specifically, the present invention relates to a bicycle internal hub transmission that includes a planetary gear mechanism.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle internal hub transmission. Internal hub transmissions are popular because all transmission components are concealed within a hub shell and are not visible.
Conventional bicycle internal hub transmissions typically include a planetary gear mechanism. Some bicycle internal hub transmissions include more than one planetary gear mechanism. The planetary gear mechanism typically includes a sun gear with one or more planetary gears engaging and rotating about the sun gear. In conventional planetary gear mechanisms, the sun gear and planetary gear(s) typically have straight gear teeth commonly known as spur gears. A problem with conventional bicycle internal hub transmissions is that as the spur gears can be noisy. A cyclist riding a bicycle with a bicycle internal hub transmission having spur gears can hear such noise and may feel insecure about the operation of the bicycle internal hub transmission even though there is nothing mechanically wrong with the bicycle internal hub transmission.
Also, although spur gears are generally reliable when employed in mechanical devices such as in a bicycle internal hub transmission, the meshing of spur gears has a potential energy transmission inefficiency when used in planetary gear mechanism(s) of a bicycle internal hub transmission.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle internal hub transmission that eliminates such noise during operation and improves efficiency. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.